By Jeremy S
Fairly new from HERA Arms — imported and sold in the U.S. by LAN World — is the SFU, or Side Folding Unit. This stock adapter allows for folding the buttstock to the side and fits any rifle that accepts an AR-15 receiver extension (buffer tube). However, it probably won’t work on your AR-15. . .
The SFU is one sleek, slim, lightweight folding adapter. There are certainly a lot of clunky ones on the market, and this ain’t one of ’em. It looks like this on the top:
…this on the bottom, with a good view of how thick that steel hinge pin is:
…and this on the push-button release side:
As you can see, the SFU is the same diameter as a castle nut, providing a sleek, in-line appearance.
I’ve actually installed mine upside down so the stock folds to the right side, but it’s really designed specifically for folding to the left. When installed correctly, a castle nut isn’t even needed. A set screw inserts in the threaded hole on bottom, indexing with the …read more
Source:: Truth About Guns